Impact of Gadoxetic acid (Gd-EOB-DTPA)-enhanced MR on the non-invasive diagnosis of small hepatocellular carcinoma.

Background: Gadoxetic acid (Gd-EOB-DTPA) is a “hepatocyte-specific” contrast agent for magnetic resonance (MR), taken up by hepatocytes, and thus producing both vascular and hepatocyte-specific MR patterns. Aim: To assess the diagnostic contribution of Gd-EOB-DTPA MR, including the added value of hepatocyte-specific phase images, in the recall diagnostic strategy of small liver nodules emerged during surveillance program of cirrhotic patients. Methods: Forthy-one consecutive small (10-30 mm) liver nodules detected at ultrasonography in 26 patients with cirrhosis were prospectively submitted to contrast-enhanced ultrasound, helical-computed tomography, and Gd-EOBDTPA MR. The diagnosis of HCC was made according to AASLD 2005 criteria. Results: Among the 41 nodules, 30 (73%) received a final diagnosis of HCC. Overall, Gd-EOB-DTPA MR was the most sensitive technique for detecting the typical vascular pattern (arterial hypervascularity followed by venous wash-out) which was observed in 25/30 (RMN vs CT: 80% vs 63%, p=0.2; RMN vs CEUS: 80% vs 43%, p=0.007; CT vs CEUS: 63% vs 43%, p=0.19, Fisher’s exact test). HCC (leading to 5 “hypovascular” HCC). Thirty-four nodules were hypointense during hepatocyte-specific phase: all of the 30 HCC nodules (100%) and 4 non-malignant nodules at biopsy, 2 of which receiving however a diagnosis of HCC during the follow-up. All of the 5 “hypovascular” HCC nodules appeared hypointense both in the venous and hepatocyte-specific phase of Gd-EOB-DTPA MR. Conclusions: Gd-EOB-DTPA MR may increase the diagnostic potential of non-invasive techniques, especially for HCC lacking a typical vascular pattern. Double hypointensity at Gd-EOB-DTPA MR, on venous and hepatocyte-specific phases, could be considered as a new radiological pattern highly suggestive for early HCC.